We all develop allergies over time. Some people become lactose intolerant. Some develop allergies to wheat. Even if you ate a ton of ice cream as a child, you might find as you age that ice cream gives you bloating problems.

Be aware of how you react to food. Every once in a while, go on a multi-day "simple fast" where you eat only simple foods and cut out typical allergens. See how your body reacts. If you develop an allergy, be aware of how it affects you.